Questions and exercises are given by the computer, which decides ______ to move the students ahead, review an easier level, ____ give more work on the same level.
---Where did you meet him? ---It was in the hotel _________ I was staying.
Can you give me a case ______ this phrase can be used?
Recently I bought an ancient Chinese vase, ______ was very reasonable.
The villagers, _________ had been damaged by the flood, were given help by the Red Cross.
With so much work his head all day long,he feels rather stressed in his daily life.